In semiconductor storage devices, at the time of reading of data from a memory cell, in order to correct an operation timing of a sense amplifier according to variation of a cell current due to variation of process conditions and operating conditions, there is a method in which the cell current flowing in a memory cell is simulated by a replica cell and the operation timing of the sense amplifier is controlled based on a monitor result of the cell current simulated in the replica cell.
On the other hand, the cell current varies in each memory cell, so that, in order to prevent occurrence of a read failure even in a memory cell whose cell current is the lowest, a margin of the operation timing of the sense amplifier is set according to the width of the distribution of the cell current.
The margin needed at this time varies depending on the process conditions and the operating conditions. Therefore, when the margin is set corresponding to the worst process conditions or the worst operating conditions, the margin becomes excessive in the best process conditions or the best operating conditions, which causes deterioration in access time.